Ortho- Fixed appliances Flashcards
What is a fixed orthodontic appliance?
An appliance that is fitted to the teeth and cannot be removed by the patient.
List some advantages and disadvantages of a fixed orthodontic appliance?
Adv-
You can change the roots
0.9mm HSSW is used in fixed orthodontics
Can achieve bodily movement (take the whole root through)
Disadv- anchorage difficulties.
What do we use a fixed orthodontic appliance for?
Closing/ creating spaces
Camoflauge (accepting the underlying skeletal base)
Overbites and overjet reduction
alignment of teeth
correction of rotations
Centreline correction
Vertical tooth movement.
What is this?
Ligature or module. This is an elastic or wire band that holds the archwire onto the bracket.
What is this?
The archwire.
This is tied to the brackets and creates force to move the teeth into proper alignment.
What is this?
The bracket- this is attached to the tooth & holds the archwire in place.
What is this?
Metal band- a cemented ring of metal which wraps around the tooth. this is used for heavily restored teeth which are unable to bond.
What is this?
elastic hooks and rubber bands.
The elastic hooks are used for the attachment of rubber bands which help to move teeth toward their final position.
How are the brackets bonded to the teeth?
via acid etch technique (although self etching can remove moisture control issues)
compare pre-coated brackets to brackets that are coated before application?
Precoated brackets are more expensive and take less time to apply as you don’t need to remove excess flash.
brackets that need to be coated before application take longer and it is difficult to control how much composite is used (so there is more flash to remove)
what are the different anchorage options for a fixed orthodontic appliance?
Simple anchorage- anchorage to a bigger tooth (so the smaller tooth will move more than the bigger tooth)
complex anchorage- anchorage on multiple teeth increases the surface area meaning less unwanted tooth movement.
Reciprocal anchorage- equal force and therefore equal movement.
Absolute anchorage- Use of Temporary anchorage devcies (TAD) which is a non-osteointegrating mini screw.
Name some force generating components found in a fixed orthodontic appliance?
Elastic power chains for space closure
NiTi coils for opening the space
Intra-oral elastics (rely on patient complaince as elastics need to be changed every day)
Active ligatures.
Trans-palatal arch- 0.9mm HSSW.
Commonly attached to the 1st permanent molars.
Used if the molars are in the ideal position.
The wire doesn’t touch the palate to prevent tissue growing over it.
This is used for anchorage/ rotation and limited widening or contraction.
Name and describe this fixed appliance ?
Quadhelix- has 4 coils.
Used for:
* expansion (Bilateral/ asymetrical/ fan style)
* Rotation of molars
* Expansion in cleft lip and palate.
* Assisiting in habit breaking to prevent achievement of the posterior seal needed for sucking.
Name and describe this fixed appliance ?
Palatal arch with nance button-
There is an acrylic button that touches the palate. This is used for anchorage.
This should be inactive (with a force applying backwards and a force applying forwards)
Disadvantage- The palate can be inflamed around the button
Identify this retainer type and list some advantages and disadvantages.
Hawley retainer
Adv-
Does not cover the occlusal surface (allows occlusal settling)
No preparation of teeth needed.
Incorporates all the teeth.
Good OH (removable)
Disadv-
Compliance (because of aesthetic)
Big and bulky- causing increased salivation & impinging on tongue space.
Expensive and time consuming to make (URA without the active component)
Identify this retainer type and list some advantages and disadvantages.
a thermoplastic retainer
Adv- aesthetic
covers all the teeth
Removable so good OH.
No preparation of teeth needed
Better tolerated (doesn’t impinge on tongue space)
Cheap to make.
Disadv-
Staining
Can be easily lost
compliance- won’t work if the patient doesn’t wear it.
Props the teeth open (occlusion can’t settle)
Prevents saliva from remineralising the tooth tissue.
Will distort if cleaned in hot water.
Identify this retainer type and list some advantages and disadvantages.
Fixed retainers
Adv- it cannot be removed (patient compliance)
Brilliant for maintaining diastemas.
Cheap
small and unobtrusive.
Disadv-
High failure rate
requires tooth preparation (acid etch)
Does not incorporate all of the teeth
Cannot be removed (OH problem)
Can debond without the patient knowing.
